It is known that alkali metal hydrogen sulphites can be added to double bonds activated by electron-attracting groups, for example, nitrile or ester groups (cf. R.T.E. Scheneck and J. Danishefsky, J. Org. Chem. 16, 1683 (1951); O. Bayer, Ang. Chem. 61, 233 (1949)). It is also known that bisulphites can be added to aliphatic double bonds which are only weakly activated. It is described for example, in the literature that bisulphites can be added by allyl alcohol (cf. M.S. Kharasch, E.M. May and F.R. Mayo, J. Org. Chem. 3, 175 (1939)). This reaction produced 3-hydroxy propane sulphonic acid in the form of its salts in a yield of only 30%. The yield obtained from the reaction of allyl alcohol and bisulphites was increased (German Pat. No. 915,693), but unfortunately, it was not possible to completely suppress the formation of secondary products, which are assumed to be compounds of the following structure: ##STR1##
Additionally, complete separation of the inorganic salts formed during reaction from the sulphonate is difficult.
Salts of 3-hydroxy-2-hydroxy methyl propane sulphonic acid are also known. Salts of this kind can be obtained by reacting 2-methylene-1,3-propane diol with bisulphites (DOS 2,224,304). However, 2-methylene-1,3-propane diol can only be obtained at high cost and in small quantities, with the result that the 3-hydroxy-2-hydroxy methyl-1-propane sulphonic acid obtained therefrom cannot be used on a wide scale. In addition, it is relatively difficult to separate this 3-hydroxy-2-hydroxy methyl propane sulphonic acid from the organic salts formed during the reaction. This also applies to the production of 1,4-dihydroxy-2-butane sulphonic acid which may be used for the preparation of stable baths used for copper plating in the absence of an electrical current (DOS 2,132,003).
Accordingly, there is a need for diols containing sulphonate groups which can be produced easily and inexpensively and which, in addition, may be used for a variety of applications by virtue of their favorable properties.